Green Energy and Technology, The Role of Exergy in Energy and the Environment, S. Nižetić,A. Papadopoulos, Editör, Springer Nature, Split, ss.363-372, 2018
The use of abundant waste materials with high
carbohydrate content may contribute substantially to reduction of biofuels
production costs. The kitchen waste fraction in municipal solid waste contains
high organic matter particulary carbohydrate that can be contributed to
fermentable sugar production for subsequent conversion to bioethanol. This
research reviews pretreatment techniques to enhance digestion of kitchen waste,
including mechanical, thermal, chemical and biological methods for bioethanol
production. The present studies aimed at optimizing the effect of different
pretreatment methods are discussed independently and its combination for
maximizing the production of fermentable soluble sugars. To this end, acid
pretreatment of kitchen waste samples was performed with sulphuric acid (0-5% H2SO4)
and hydrochloric acid (0-5% HCl) at 30-100°C for 0-120 min treatment time.
Alternatively, alkaline pretreatment was performed with sodium hydroxide
solution (0-5% NaOH) at 30-120°C for 0-120 min treatment time. Both acid and
alkaline pretreatments were combined with enzymatic hydrolysis (170mg protein/kg
wet waste) at constant pH, temperature and time (pH:4.8, 50°C and 6h
respectively). The effectiveness of each pretreatmant method was compared based
on percentage of glucose recovery. Changes in structure of kitchen waste was
also observed microscopically (SEM) and spectroscopically (FTIR) leading to
enhance the digestibility of kitchen waste with different liquefaction methods
and its combination.